package common.server.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.security.Key;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

/**
 * DES加密工具
 * @author Administrator
 * @version [版本号, 2018/3/6 0006]
 * @see [相关类/方法]
 * @since [产品/模块版本]
 */
public class DesUtils {

    private static final String DES_KEY = "com-bigwavn-touch";

    public static final String ALGORITHM_DES = "DES/ECB/PKCS5Padding";

    /**
     *
     */
    private static Logger logger = LoggerFactory.getLogger(DesUtils.class);

    /**
     * 加密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public static String encodeByDefaultKey(String data) throws Exception {
        return encode(DES_KEY, data.getBytes());
    }

    /**
     * 解密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public static String decodeByDefaultKey(String data) throws Exception {
        return decodeValue(DES_KEY, data);
    }

    /**
     * DES算法，加密
     *
     * @param data
     *            待加密字符串
     * @param key
     *            加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     * @throws Exception
     *             异常
     */
    public static String encode(String key, String data) throws Exception {
        return encode(key, data.getBytes());
    }

    /**
     * DES算法，加密
     *
     * @param data
     *            待加密字符串
     * @param key
     *            加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     * @throws Exception
     *             异常
     */
    public static String encode(String key, byte[] data) throws Exception {
        try {
            DESKeySpec dks = new DESKeySpec(key.getBytes());
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            // key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec("********".getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, new SecureRandom());
            byte[] bytes = cipher.doFinal(data);
            return Base64.encode(bytes);
        } catch (Exception e) {
            throw new Exception(e);
        }
    }

    /**
     * DES算法，解密
     *
     * @param data
     *            待解密字符串
     * @param key
     *            解密私钥，长度不能够小于8位
     * @return 解密后的字节数组
     * @throws Exception
     *             异常
     */
    public static byte[] decode(String key, byte[] data) throws Exception {
        try {
            SecureRandom sr = new SecureRandom();
            DESKeySpec dks = new DESKeySpec(key.getBytes());
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            // key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec("********".getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.DECRYPT_MODE, secretKey, new SecureRandom());
            return cipher.doFinal(data);
        } catch (Exception e) {
            throw new Exception(e);
        }
    }

    /**
     * 获取编码后的值
     *
     * @param key
     * @param data
     * @return
     * @throws Exception
     * @throws Exception
     */
    public static String decodeValue(String key, String data) throws Exception {
        byte[] datas;
        String value = null;
        datas = decode(key, Base64.decode(data));
        value = new String(datas);
        if (value.equals("")) {
            throw new Exception();
        }
        return value;
    }

    public static void main(String[] args) throws Exception {
        String iphone = "15876543210";
        String es = encodeByDefaultKey(iphone);

        System.out.println("密文:" + es);
        System.out.println("明文:" + decodeByDefaultKey(es));
    }
}
